Is my tank over stocked?

I think that you might want to provide enough fish for a school of some of your tetras, but I don't think that there is enough capacity in the tank to add too many. Removal of some fish and then addition to the remaining schooling fish would be a good bet. As for bottom dwellers, I will suggest Cories and Otos. They're my personal faves for the bottom of a tank, but I am sure that you will get other suggestions.

I believe you have room to safely add around half a dozen more fish.

As far as bottom dwellers, I prefer Clown loaches (you need at least 3), Apistogrammas or Cories

The problem is the mention of the 37g high tank. This greatly reduces the amount of gas exchange which could happen without some subtantial aeration and thus agitation of the surface. I agree that there is room for a few more fish, but not too many due to the lowered amount of gas exchange.

The number of fish means nothing without considering size. For example, my 12" pleco produces a lot more waste than a school of 8 1-1/2" cardinals.

Whether or not you are overstocked also depends on how much filtration you have and whether or not you're concerned about what will happen in a power outage. I.e. if the power goes out, your filter and heater will turn off - but more importantly, there will be virtually no surface disturbance, which is what dissolves the oxygen your fish breathe.

Also this is more of an art than a science. You will hear people say one inch of fish per gallon of water, one inch of fish per 10-12 square inches of surface area, or whatever. Those are good guidelines, but you can fool yourself into thinking you're not overstocked if your fish survive because you have good filtration and the power doesn't go off for long.

Max size x number of fish = Inches of fish
5 congo tetras = 15" of fish
3 scissortail rasboras = 15" of fish
2 ottos = 4" of fish
2 glass catfish = 8" of fish
3 pristella tetras = 6" of fish
1 red serpae tetra = 2" of fish
1 black skirt tetra = 2" of fish
1 yo yo loach = 5" of fish

Giving a total of 57 inches of fish in a 37 gallon aquarium.

That is a lot more fish than I would be comfortable with in my aquarium. However many people would be comfortable with this, and maybe even put more in there. Like I said, if you have good filtration and don't have any extended power outages, you may be fine. If the power goes out for any significant length of time, you're probably going to have losses.

Good reasoning and explanation Heady, I fully agree.

To me the tank is overstocked, but it is sustainable with good filtration and good maintenance so long as there are no problems. If problems arise with power outage, high temperatures, disease, etc., the slippery slope is steep and fast.

i say you have room for a few more but advise add some that hang out at the bottom all the fish you have like the upper level of the aquarium.

Heady, well while I don't disagree with your concept, I do disagree with your application of it.

You are way too aggressive on the maximum size for almost all those fish IMO. Just my opinion.

Most of those maximum sizes were obtained right here from aquaria central; for the ones that aquaria central did not list, I checked at least 2 different websites before settling on a size. Whether fish are actually kept healthy enough to reach their maximum size is another story.